With a silicon carbide power semiconductor, a high channel mobility is required to reduce resistance at a channel portion in order to realize low on-resistance. Hence, it is indispensable to suppress the interface state low in the interface between silicon carbide and silicon dioxide. Further, it is necessary to decrease contact resistance in a source region.
It is demanded to increase the activation rate of these implanted ion species to reduce contact resistance with an electrode and reduce switching loss. When heating processing is performed at a superhigh temperature such as 1900° C. to 2000° C. to activate implanted ion species, the activation rate is increased by a mechanism which can restore lattice damage upon ion implantation.
However, a processing temperature is superhigh, and therefore that contradicting negative influences (hereinafter, referred to as “negative influences due to first heating processing”) such as sublimation from a silicon carbide surface and resolution and withdrawal of silicon also cause an increasingly remarkable temperature region causes an influence. When a silicon dioxide film is formed on the surface of silicon carbide for which this heating processing is performed at a superhigh temperature to manufacture a MOSFET, the interface state density in the interface between silicon carbide and silicon dioxide substantially rises. Further, even if various atmosphere processings after formation of an oxide film are executed, there is a new problem that the interface between silicon carbide and silicon dioxide with a low interface state density can no longer be realized.
Furthermore, although, when a Schottky barrier diode is manufactured, it is possible to reduce contact resistance similar to manufacturing of a MOSFET, there is a new problem that a backward leakage current increases.
As is observed upon manufacturing of the above MOSFET or a Schottky barrier diode, while a bipolar PiN diode can reduce contact resistance, there is a new problem that an on-voltage rises.